Investigation of environmental health indicators in swimming pools located in the east of Tehran, Iran

Swimming pool environments may cause various diseases to swimmers due to the transmission of microbial contamination if not maintained properly. Therefore, the aim of this study was to investigate the bacterial contaminations in four swimming pools in the east of Tehran, Iran. Samples were collected from five sampling points (low depth, regular depth, deep, hot tub, and cooling pond) twice in a month during the summer season (June–August 2019). A total number of 120 samples were taken from swimming pools, as recommended by national standards. The bacterial contamination (coliform, heterotrophic, Staphylococcus aureus , and Pseudomonas aeruginosa ), together with physical–chemical parameters, was measured. Average values for residual chlorine and pH were found in accordance with the national guidelines ( P > 0.05). In contrast, the mean value for turbidity was not in compliance with the national standards ( P ≤ 0.001). Moreover, the prevalence of coliforms, heterotrophic bacteria, P. aeruginosa , and Staphylococcus aureus was at acceptable levels of 100, 97.5, 97.5, and 90.2%, respectively. Additionally, a direct association was found between turbidity and pH ( r = 0.396) as well as P. aeruginosa ( r = 1.182) and S. aureus ( r = 0.275). Unlike turbidity, residual chlorine showed a weak and inverse relationship with S. aureus ( r = – 0.257). Results indicated that the average microbial quality of swimming pool water was at desirable levels. However, to improve the hygienic condition of pools, periodic monitoring of above-mentioned indicators and training of pool operators are necessary. Further, studies on other physical, chemical, and biological contaminations may be required.